ABSTRACT One of the earliest postnatal risk factors for obesity is rapid weight gain during early infancy and formula-fed infants are at greater risk for excessive weight gain than breastfed infants. There are many benefits of exclusive breastfeeding, making promotion of breastfeeding the ideal. However, significant proportions of mothers formula-feed, either exclusively or in combination with breastfeeding, and these mothers report a lack of support for learning and adopting healthy bottle-feeding practices. A growing body of evidence suggests that formula-feeding mothers may develop more controlling feeding practices due to their ability to feed in response to amount of formula in the bottle, instead of in response to infant satiety cues, leading to overfeeding, rapid weight gain, and risk for obesity. The overall objective of the proposed pilot/feasibility study is to evaluate a home- and family-based intervention to increase formula-feeding mothers? responsiveness to infant satiety cues and moderate formula-feeding infants? rates of weight gain over a 12-week period. Specifically, we propose to provide mothers with opaque, weighted bottles (instead of conventional, clear bottles) with which to feed their infants; based on our preliminary studies, we hypothesize that removal of mothers? abilities to assess the amount the infant consumes during a feeding will facilitate abilities to feed in response to infant satiation cues.For the proposed research, exclusively formula-feeding mothers with <2-week-old infants will be randomized to use weighted, opaque bottles (intervention or opaque group) or to use their preferred, clear bottles (control or clear group). We will conduct home-based assessments at the beginning and end of the 12- week study period, during which we will video-record mothers feeding their infants using clear or opaque bottles. We will also conduct two interim home assessments (after 2 and 6 weeks) to assess feeding adequacy and fidelity to the intervention. During feeding observations, infant intake will be assessed via bottle weight. Video-records will be later coded for maternal responsiveness to infant cues using the Nursing Child Assessment Parent-Child Interaction Feeding Scale (NCAFS). We hypothesize that mothers in the opaque group will feed their infants less and show greater increases in their levels of responsiveness to infant cues compared to mothers in the clear group. Infants? weight and length will be measured at the beginning and end of the 12-week study; weight-for-length z-scores (WLZ) will be calculated using the WHO Growth Standards. We hypothesize that WLZ change will be significantly lower for infants in the opaque compared to the clear group. We will also explore the feasibility of our intervention by collecting and analyzing objective and subjective data related to the extent to which mothers use and like the bottles, and whether characteristics of mothers or infants moderate intervention effects. The proposed feasibility study is a critical step toward understanding mothers? acceptance and use of opaque bottles compared to conventional, clear bottles, and the potential for opaque bottles to improve the outcome of feeding interactions in home-based settings.